Broom Court Care Home

Blackwood Homes & Care required support from industry professionals to assist in their ‘Grey Fleet to Green Fleet’ project, supported by the Scottish Government’s Low Carbon Infrastructure Transition Programme. Emtec Energy were appointed Principal Contractor to find a solution through the installation of energy efficient and renewable technologies, this included solar PV, LED lighting, energy monitoring equipment and a battery storage system.

The project aims to act as a demonstrator, through development of a local energy and transport system integrating renewable energy generation (solar PV), battery storage and self-consumption, and a local electric vehicle fleet. The demonstrator system will show how reductions in care home operational running costs and carbon emissions associated with building operation and car/vehicle transport are possible, whilst improving care to residents in the community through expanding the potential sphere of influence of service providers.

Overall, Blackwood’s goal is to achieve lower running costs by optimising the use of a solar photovoltaic (PV) systems on one of their care homes in Stirling. This 111.3kW solar PV system is installed across 19 roofs at Broom Court, including Blackwood offices and residential care homes. As the solar PV system will act as the main supply of electricity to the site, it was imperative that maximum yield was captured. Each of the 420 solar modules are connected to SolarEdge optimisers and ultimately to 5 SolarEdge string inverters installed throughout the site. As each solar module is independently optimised, the annual yield of the system will be greater than that of a traditional solar PV installation using string inverters.

The energy from the scheme is stored within a 128kW battery storage system. This system includes ten 12.8kW BYD B-Plus battery storage units, located in the plant room of the care home. To ensure the battery storage system is suitable for on-site charging, the batteries are connected to six Victron Quattro Inverter/Chargers, which transfer the current from AC to DC. This system is set up to provide immediate and latent renewable electricity to the care home and provide a power supply back-up.

Rewiring of the main board was required to supply essential loads if – and when – there is a loss of mains to the facility. As a result, a minimum of 2 hours’ electrical back-up for the Care Home is retained in the battery storage system at all times when there is normal connection to the electrical grid, this provides the emergency back-up for the building. This allows Blackwood to maintain a reliable supply of power to the care home, ensuring the day-to-day running of the properties is not disrupted.

This project also included the installation of Electric Vehicle chargers on site, further supporting the abilities of the solar PV installation by offering the potential to control and supply energy to the chargers during periods of peak supply.

The power generated would be monitored and controlled through an energy management system. This allows the electrical usage within the building, for charging the battery storage units and EV chargers, to be prioritised over grid export from the solar PV installation.

Overall System Sizes

Overall, the solar PV system is expected to yield 93,348kWh per annum, saving over 46,114kg of CO₂ emissions a year. The total yield provides 35.2% of building demand at 32,863kWh a year. Approximately 26.1% of the yield will charge the battery, providing 23.2% as a backup and when supply from solar is low, while the other 2.9% will feed into the EV chargers. The remaining 38.7% (36,167kWh) is likely to be exported.

The amount of solar generation used in-house equates to 57,181kWh per annum. This means the battery storage units increase the level of solar used on site from 35.2% to 61.3%. Over the course of a year this will save 24,318kWh from being imported, resulting in a reduction of 12,013kg of CO2 emissions. Ergo, while the solar PV system will provide significant savings overall, the battery storage system alone greatly helps Blackwood reduce emissions and become less reliant on the grid.

Emtec performance by all personnel involved - design, project management & the site installation team on this innovative Solar PV/Battery Storage project was impressive. All challenges were met with due regard to this being an operational Care Home setting & has delivered to expectations.

Mike Wagner, Assets Consultant for Blackwood Group

This installation has been nominated for 'Residential, commercial and industrial energy storage project of the year' at the upcoming Solar Power Portal Awards. For more information on the event see here.